by Karen Weintraub, Special for USA TODAY

by Karen Weintraub, Special for USA TODAY

His muscles ached like nothing he'd ever felt before as he passed Mile 13. Pushing against a runner's wall and a strong headwind, it was like running uphill the whole way. As a distraction, Alok Gupta reminded himself, as he often has these past four months, why he voluntarily subjected himself to such torture.

If his former patients could survive twin explosions, multiple surgeries, physical therapy and the emotional strain of last April's Boston Marathon bombings, he thought, he could certainly run a few - OK, 26 - miles in their honor.

Gupta, a trauma surgeon, helped coordinate the response at Beth Israel Deaconess Medical Center, one of five trauma centers that received patients that day. He also was involved in the care of Dzhokhar Tsarnaev, the surviving brother who has been charged in the attack that killed three and wounded more than 260.

Now, Gupta, 37, is one of 70 Beth Israel staff members training for this year's Boston Marathon on April 21. Like many other Bostonians, they feel a compulsion to run to honor the injured and prove that the city will not be cowed by terrorists, homegrown or otherwise.

Overall, 36,000 marathoners will don running shoes and numbers this year - up from 27,000 last year - plus an additional 10,000 will run a 5K race. Other area hospitals that treated victims are seeing a spike in the number of staffers who will run. At Boston Medical Center, the marathon team numbers 105 this year, up from 35 last year. At Brigham and Women's Hospital, the team is up to 122 participants from 67. More than 200 are running on Massachusetts General Hospital's team, up from 119 last year. Many, like Gupta, are tackling their first marathon.

Most of the medical personnel talk about the solidarity they feel with last year's victims, whether they treated them or not.

Tamara Rozental, an orthopedic surgeon at Beth Israel and a longtime runner of shorter distances, says three things prompted her to tackle the marathon. One was the patients she treated last April. "If they can go through something like that, I can run 26 miles," she says. The second was to pay tribute to her medical colleagues: "Nobody who made it to a hospital that day died. That's a pretty amazing thing." She's also running for her two daughters, the older of whom was born on Marathon Monday six years ago: "I want to show my daughters you can do anything you want to do."

For Rozental, the step up to a marathon was relatively easy. After a long day at the hospital, she says, running is meditative, a refreshing break and a time to review her caseload or think through a problem. Last year's tragedy left her with a lot on her mind, so her long runs had already kept edging up. It didn't seem like such a leap to go for 26 miles, she says, though she has new respect for marathoners. "Now I understand what it takes."

For Gupta, the transition has been much tougher. He'd never run more than a few miles at a time, and that was in high school.

"Before all this happened, I used to ask people (who were running marathons), 'What would possess you to do something so silly?'" he says.

HE TRAINED FOR THIS

When Gupta relives last year's marathon in his mind, he starts with the minute he came in the door from an early shift at work, eager to take his 3-month-old daughter to the finish line. It was an annual tradition for him to walk the few blocks from his apartment to celebrate the runners' success.

But she was napping, so Gupta resigned himself to waiting awhile and seeing only the slowest of finishers. Then his phone rang. The connection was terrible, but he made out the word "bomb." Less than a minute later, after making sure his mother-in-law could stay with the baby, Gupta rushed out the door. He arrived at Beth Israel's emergency room just ahead of the first victims.

He had trained for moments such as this for years through medical school simulations and during the 9/11 attacks, when he was a medical student in New York's Jacobi Medical Center. He assumed he'd never experience such a mass tragedy again.

This time, at Beth Israel, he was in charge.

Gupta identified the most grievously injured patients and made sure the treatment teams were well matched to those 24 patients' specific problems: an orthopedic surgeon for a man with an injured leg; a vascular one for the patient losing too much blood.

It wasn't until a few hours later that the thought crossed his mind: It could have been me.

If his daughter hadn't been napping, he would have bundled her into her stroller and walked to his traditional spot near the finish line - right near where one of the bombs went off.

Struggling toward the hills of the Boston suburb of Newton on his recent training run, getting close to his target distance for the day, Gupta focuses on one footfall at a time. It's what physical therapists tell their patients who are learning to walk again: Take it one step at a time.

A few of his patients from that haunting day would have to adjust to life with just one leg. Others had perforated eardrums, head injuries or other leg wounds.

MOVING FORWARD

A few days after the attack, when patients and families began asking to meet other survivors, Gupta arranged to have a room set aside where they could gather and share their stories. The dedicated space allowed them to go or stay as they wished, without compromising their privacy.

Then, after all the patients were discharged - the last one went home 50 days after the bombing - Gupta set up a clinic for the victims. He didn't want them to have to come to the hospital multiple times to meet with different specialists, so he had the specialists come to them, packing a half-dozen follow-up appointments into a few hours.

Gupta is proud of how his hospital and his community handled the bombings. He has given a dozen speeches about it since and is preparing a paper with colleagues on lessons learned. There will be more tragedies for people in his field to cope with. There always are.

Just before Mile 18 on his recent training run - 3½ hours after leaving from the Hopkinton, Mass., starting line and 5 miles after the searing pain started - he reaches a hill in Newton. He can't stop short of his goal, so he climbs, one step at a time, to the top.

From the summit, he decides he can't deprive himself the pleasure of going down, so he keeps on. He runs a few more hills, a few more summits before he finally stops, within sight of the marathon landmark known as Heartbreak Hill.

Gupta, after running at least 6.2 miles longer than he ever thought possible, still can't picture what it will be like when he crosses that finish line April 21.

But, he promises, he'll get there, despite whatever pain he feels that day, alongside 36,000 other runners, many of whom hold the same goals.